Software-defined network (SDN) architecture enables network programmability to support multi-vendor, multi-technology, multi-layer communications and offers network infrastructure as a service. Efforts to integrate optical transport within IP/Ethernet based SDN architectures are ongoing with the goal of leveraging optical transmission benefits, such as low interference, long reach, and high capacity transmission with lower power consumption. Such a network is known as a transport SDN.
Transport SDNs are implemented by enabling flexibility and programmability in wavelength division multiplexing (WDM) transmission and switching network elements, such as transponders and reconfigurable optical add-drop multiplexers (ROADMs), management of optical channels such as with flexible-grid channel mapping, and extracting control plane intelligence from the physical hardware to a centralized controller.
Network virtualization is one technology being explored, as since it supports applications and services by sharing network resources within the existing deployed infrastructure instead of building new networks from scratch. In software-defined flexible-grid transport networks, an open control plane challenge is how to map Virtual network Infrastructure (VI) demands over multi-layers of physical substrates. A VI demand is a set of Virtual Nodes (VNs) interconnected by a set of Virtual Links (VLs). The problem is how to map VNs over Physical Nodes (PNs), how to map VLs over transport connections, how to route transport connections over Physical Links (PLs), and how to assign spectral resources to the transport connections.